More than 90,000 adults have undergone living donor nephrectomy in the United States over the last 20 years. Live donor kidney transplantation (LDKT) is important because its outcomes for recipients are superior to those of deceased donor transplantation, and it yields significant cost savings to the healthcare system overall. Despite efforts over the past few decades to enhance understanding of the short- and long-term outcomes of living kidney donation, it is clear that we have more knowledge in some areas (e.g., surgical and medical complications) than in others (e.g., psychological outcomes, financial impact). While the transplant community and changes in federal regulations have brought attention to the need for more systematic study of living donor outcomes, there remains a paucity of scientifically rigorous multisite, prospective outcome studies. The long-term goal of our research program is to characterize the short- and long-term surgical, medical, functional, psychological, and financial outcomes of living kidney donation. The objective of this application, which is the next step in pursuit of that goal, is to establish a multisite prospective cohort of living kidney donors (n=240), their recipients (n=240), and a healthy comparison group (n=240). This cohort will be used to examine three primary aims: (1) to assess donor outcomes (surgical, medical, functional, psychological, financial) over a 2-year period initially, with the intention of examining these outcomes over a more extended time period in subsequent years; (2) to identify the donor, recipient, and center variables that are most predictive of donor outcomes; and (3) to identify disparities in donor outcomes and their predictors. To accomplish these aims, six kidney transplant programs, representing six states (Massachusetts, Maine, Rhode Island, Florida, Iowa, and Arizona) and with experience and expertise in caring for living donors and transplant recipients, will participate in the study. Donors, their recipients, and healthy controls will complete comprehensive assessments at baseline (pre-surgery) and at 1, 6, 12, and 24 months post-donation. This study will extend our considerable preliminary work by simultaneously examining outcomes that are of importance to donors, recipients, healthcare providers, and policymakers. The rationale for the proposed research is that, once these outcomes and their predictors are known, we can further develop and refine educational strategies and informed consent processes for both living donors and their intended recipients, as well as provide systematic data to inform policy discussions and clinical care practice.